Contractors Should Be Aware of Regulations Before Using Drones on Construction Sites

This article is intended for educational purposes only and should not be construed as legal advice. For legal advice about the use of drones, contact an attorney.

The 21st century has brought with it explosive growth in technology that is changing the world we live in on a daily basis. New innovations are allowing for more efficient ways to do business in various industries; the construction industry is no exception.

Among the more controversial innovations with vast potential to revolutionize construction work is the Unmanned Aircraft System, or UAS, which is more commonly known as a drone. These remote-controlled flying robots have already found their way onto construction sites around the country, and use is proliferating as entrepreneurs discover more ways to apply drones to commercial uses. Although drones may yield numerous benefits to contractors, they have also created a need for new regulations to allow them to fit into the national legal landscape. As a result, contractors wishing to employ drones on their construction sites must be aware of such regulations.

BENEFITS OF DRONES

The application of drones to construction work has begun to yield advantages in several areas, including marketing, inspections and surveys.

Traditionally contractors have presented their ideas and progress to their customers through a combination of diagrams and photographs of the site. Drones allow contractors to show off their work in a new way. By attaching a video camera to a drone and sending it through and around a construction site, contractors can provide customers a fully immersive virtual tour of the site, including aerial views and observations of areas that otherwise would be difficult to reach. This new marketing tool will surely be a boon by visually enhancing the viewer’s experience.

Drones also have the potential to more efficiently monitor the activities of workers on a job site for progress and ensure all workplace policies are being followed. Because construction sites involve the work of many people, usually in different areas that can be difficult to reach, a small flying camera can quickly and efficiently aid site superintendents in monitoring projects.

Another area in which drones have begun to make an impact is surveys. In the past, surveyors have completed their work by carefully drawing lines and manually measuring distances. Today, drone technology allows for much larger areas to be covered in much less time. A drone can be synced with GPS technology to create a quick, reliable, mobile mapping system or with thermal imaging systems for thermodiagnostics, assessment of damage and estimating of projects.

LEGAL CONCERNS FOR CONTRACTORS

Before applying drones to a worksite, however, construction professionals must be aware of several laws that will affect their use. Many laws that have been considered common practice with regard to drone use thus far have recently been nullified by a comprehensive new set of rules finalized by the Washington, D.C.-based Federal Aviation Administration on June 21. These new rules follow:

HIRE A CERTIFIED PILOT IN ADVANCE
Not just anyone can operate a drone commercially; a pilot must be certi- fied in advance. The new rules issued by the FAA include a new system for certifying drone pilots. The new system creates a certified position, “Remote Pilot in Command”, a title which can only be obtained via receiving a remote pilot certificate. Any person operating a drone must possess this certification or be under the direct supervision of someone who is certified. To qualify for the remote pilot certificate, a person must meet the following requirements:

  • Demonstrate aeronautical knowledge by either:
  • — Passing an initial aeronautical knowledge test at an FAA-approved knowledge testing center.
    — Holding a Part 61 pilot certificate other than student pilot, completing a flight review within the previous 24 months and completing a small UAS online training course provided by the FAA.

  • Be vetted by the Transportation Security Administration, Washington.
  • Be at least 16-years old.

This certification system also allows for temporary early access in certain circumstances. For example, any person certified as a Part 61 pilot will, upon submission of an application for a permanent certificate, immediately receive a temporary remote pilot certificate so he or she does not have to wait before continuing drone work. All applicants not certified under Part 61 can still receive temporary early permission; they will receive a temporary certificate after being satisfactorily vetted by the TSA. In addition, foreign pilots must meet these requirements at least until international standards are developed.

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Choosing the Right Roof Coatings for Substrates Can Extend Roof Service Lives, Cool Temperatures and Save Energy

Roof coatings are a fast-growing market segment in the roofing industry—and it makes good sense why that is the case. Application of a roof coating on a new or existing roof can provide
added durability, extend roof service life, save on energy costs, and avoid the hassle and expense of a full tear-off and replacement.

COATING TYPES

Roof coatings come in many formulations and are appropriate for installation over all roof system types. The first question many have is which coating is appropriate for which substrate?

A reflective coating has been applied to a hybrid asphaltic roof. PHOTO: GAF

A reflective coating has been applied to a hybrid asphaltic roof.
PHOTO: GAF

Coatings are most broadly divided into asphaltic- and polymer-based materials. Asphaltic-based coatings are solvent-based “cut backs” or water-based emulsions. They can be black or aluminized. They have the ability to be used in cold and inclement weather. Aluminized coatings are used when a reflective and ultraviolet-, or UV-, stable asphalt coating is needed.

The most common polymer-based coatings include acrylics, polyurethanes and silicone coatings. Acrylic water-based coatings are ideal for high UV environments where a reflective roof is desired. They can be colored but generally are sold in white, tan and gray. Many specialized versions are made to be compatible with specific substrates. Polyurethane coatings are typically solvent-based and come in two main types, aromatic and aliphatic. Urethanes have good mechanical properties and high abrasion resistance. They are suggested for use in hail-prone regions or where a roof is exposed to heavy foot traffic.

Silicone coatings, like acrylic coatings, perform well in high UV environments where a reflective roof is desired. Often silicone is used in locations where rain is a daily occurrence or if the roof is often wet and experiences excessive amounts of ponded water. In addition, butyl, fluoropolymer, PMMA, polyester, STPE, SEBS and styrene-acrylics can be used to formulate roof coatings.

Coating thickness (dry film thickness) has an effect on performance. In general, thicker coatings will have increased service life and will provide additional durability regardless of coating type. Also very important is the specification written for each project. Every project is different and every specification should be tailored to every project to ensure the correct coating and application is appropriate for the roof and coating type. Coating manufacturers’ specifications should be the basis for every coating project and be coordinated with project specifications.

SUBSTRATES

Asphaltic-based coatings are most commonly used on built-up roof (BUR) and modified bitumen (MB) membranes; they are rarely, if ever, used on single-ply roof membranes. All types of polymer-based coatings are used on BUR, MB, metal and single-ply roofs. There is information to assist with the evaluation and preparation of the substrate in the ASTM standard titled, “Standard Guide for Evaluation and Preparation of Roof Membranes for Coating Application”.

From a material-quality standpoint, it is important to use products that meet or exceed their ASTM material standards, which are listed in the International Building Code and International Residential Code. Meeting the building-code requirements provides the minimum safeguards for materials used for construction.

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Code-mandated Thermal Insulation Thicknesses Require Raising Roof Access Door and Clerestory Sill Details

PHOTO 1: The new roof has been installed at SD 73 Middle School North and it can clearly be seen that the door and louver need to be raised. On this project, there were four such conditions.

PHOTO 1: The new roof has been installed at SD 73 Middle School North and it can clearly be seen that the door and louver need to be raised. On this project, there were four such conditions.

The most common concern I hear related to increasing insulation thickness (a result of increased thermal values of tapered insulation), especially in regard to roofing removal and replacement, is, “OMG! What about the roof access door and/or clerestory?” You can also include, for those knowledgeable enough to consider it, existing through-wall flashing systems and weeps.

I’m a bit taken aback by this concern; I have been dealing with roof access doors and clerestory sills for the past 30 years and, for the most part, have had no problems. My first thought is that roof system designers are now being forced to take these conditions seriously. This is a big deal! They just have no clue.

In the next few pages, I’ll review several possible solutions to these dilemmas, provide some detailing suggestions and give you, the designer, some confidence to make these design and detailing solutions. For the purpose of this article, I will assume reroofing scenarios where the challenge is the greatest because the conditions requiring modification are existing.

THE ACCESS DOOR

For many and perhaps most contractors who sell and, dare I say, design roofs, it is the perceived “large” expense of modifying existing conditions that is most daunting. Often, these conditions are not recognized until the door sill is several inches below the new roof sur- face. Not a good predicament. Planning for and incorporating such details into the roof system design will go a long way to minimizing costs, easing coordination and bringing less tension to a project.

PHOTO 2: The sill has been raised and new hollow metal door, frame and louver have been installed at SD 73 Middle School North. Door sill and louver sill flashing are yet to be installed, as are protective rubber roof pavers.

PHOTO 2: The sill has been raised and new hollow metal door, frame and louver have been installed at SD 73 Middle School North. Door sill and louver sill flashing are yet to be installed, as are protective rubber roof pavers.

Door access to the roof is the easiest method to access a roof. These doors are typically off a stair tower or mechanical penthouse and most often less than 12 inches above the existing roof as foresight was not often provided (see photos 1, 2 and 6 through 9). With tapered insulation thickness easily exceeding 12 inches, one can see that door sills can be issues with new roof systems and need to be considered.

Designers should first assess the condition of the door and frame, typically hollow metal. Doors and frames that are heavily rusted should not be modified and reused, but discarded, and new ones should be specified. The hardware too needs to be assessed: Are the hinges free of corrosion and distortion? Is the closure still in use or detached and hanging off the door frame? The condition of door sweeps, knobs, lockset and weather stripping should also be determined. Ninety-nine percent of the time it is prudent to replace these parts.

As the roof system design develops, the designer should start to get a feel for the thickness of insulation at the door. It is very important the designer also consider the thicknesses that vapor retarders, bead and spray-foam adhesives, cover and board and protective pavers will add. These can easily be an additional 4 inches.

PHOTO 3A: The new roofing at SD 73 Elementary North was encroaching on this clerestory sill and required that it be raised. As part of this project, the steel lintel was exposed. It was prepped, primed and painted and new through-wall flashing was installed.

PHOTO 3A: The new roofing at SD 73 Elementary North was encroaching on this clerestory sill and required that it be raised. As part of this project, the steel lintel was exposed. It was prepped, primed and painted and new through-wall flashing was installed.

Once the sill height is determined, the design of the sill, door and frame can commence. If the sill height to be raised is small—1 1/2 to 3 inches—it can often be raised with wood blocking cut to fit the hollow metal frame, flashed with the roofing membrane, metal sill flashing and a new door threshold installed, and the door and frame painted. This will, of course, require the removal of the existing threshold and door which will need to be cut down to fit and then bottom-sealed with a new metal closure (see details A and B, page 3).

When the door sill needs to be raised above 3 inches, the design and door considerations increase. Let’s consider that the door and frame is set into a masonry wall of face brick with CMU backup. Although most hollow metal doors are 7 feet 2 inches to match masonry coursing, after the modification the door may be shorter. For example, if a door is 7 feet 2 inches and you must raise the sill 5 inches, the new door and frame will need to be 6 foot 9 inches.
PHOTOS & ILLUSTRATIONS: Hutchinson Design Group Ltd.

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RICOWI Provides Unbiased Research on Recent Hail Damage

Each time weather reports and news stories warn of impending heavy rains and hail, the Hail Investigation Program (HIP) Committee of the Roofing Industry Committee on Weather Issues (RICOWI) Inc., Clinton, Ohio, begins a process to determine whether the hail damage is sufficient to meet the HIP requirements for deployment of volunteer research teams.

Before the daily assignments began, the volunteers reviewed the various research requirements, met their team members and learned their responsibilities.

Before the daily assignments began, the volunteers reviewed the various research requirements, met their team members and learned their responsibilities.

Mobilization criteria is met when “An event is identified as a hailstorm with hail stones greater than 1 1/2 inches in diameter causing significant damage covering an area of 5 square miles or more on one of the target- ed areas.” Once a storm that meets the criteria has been confirmed and meteorological data and local input have been obtained by HIP, a conference call with RICOWI’s Executive Committee is held to discuss HIP’s recommendation and review information. The Executive Committee decides whether to deploy.

On April 11, 2016, the hailstorm that damaged the Dallas/Fort Worth metroplex met the requirements for mobilization.

RESEARCH TEAMS AND BUILDINGS

Volunteer recruitment is an ongoing process throughout the year. RICOWI members are encouraged to volunteer as a deployment team member by completing forms online or at HIP committee meetings held twice a year in conjunction with RICOWI seminars and meetings.

Once a deployment is called, an email is sent to RICOWI members to alert the volunteers and encourage new volunteers. RICOWI sponsoring organizations also promote the investigation to their memberships. Volunteers are a mixture of new and returning personnel.

On May 2, 2016, 30 industry professionals traveled from across the U.S. to assemble in Texas. These volunteers were alerted to bring their trucks, ladders and safety equipment. To provide an impartial review, 10 teams of three volunteers were balanced with roofing material representatives, roofing consultants or engineers, meteorologists, contractors and researchers. Team members volunteered to be their team’s photographer, data collector or team leader.

When the deployment was called, press releases were sent to various media in the Dallas/Fort Worth area to alert local companies and homeowners of the research investigation. RICOWI staff began making calls immediately to the local area’s government officials to seek approval for the investigation teams to conduct research. Staff also made calls throughout the research week to help identify additional buildings.

A large area in and around Wylie, Texas, had hail as large as 4 inches in diameter.

A large area in and around Wylie, Texas, had hail as large as 4 inches in diameter.

Several methods are used to help determine which areas and roofs are chosen. A list of building permits were provided to RICOWI by local building officials to assist with roof choice. In addition, one of RICOWI’s members from the area did preliminary research and provided addresses for the teams. These site owners were contacted through phone and email to notify them of the research project.

Teams were assigned low- or steep- slope research and were assigned addresses accordingly. Team members carried copies of the press release and additional information to help introduce the investigation to business owners and homeowners.

Ultimately, the objective of the re- search project in Dallas/Fort Worth included the following:

  • Investigate the field performance of roofing assemblies after this major hail event.
  • Factually describe roof assembly performance and modes of damage.
  • Formally report the results for substantiated hail events.

DAY-TO-DAY DUTIES

Before the daily assignments began, the volunteers reviewed the various research requirements, met their team members and learned their responsibilities. The teams were briefed on safety, how to take proper photos and how to capture important data.

As each day began, a briefing was held providing assignments for the day. This included addresses for investigation based on whether the team was focused on low- or steep-slope research. The teams were encouraged to stop at other homes and facilities that were undergoing roof repairs in addition to their assigned inspections.

The days were hot and long for the teams. Volunteers began each day at 8 a.m. and many did not return until 5 or 6 p.m., depending on the number of roofs they were assigned. The temperature during the day was around 80 F and humid; the temperatures on the roofs were much worse.

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A Roofer’s Guide to Lightning Protection

Your roof is not only a weather barrier, it is a work platform for other trades, including lightning-protection installers. Understanding a few basics about lightning protection will simplify job-site coordination and lead to more successful projects.

Lightning protection installers are highly trained craftsmen. Like roofers, they work exposed to the weather and often at dangerous heights.

Lightning protection installers are highly trained craftsmen. Like roofers, they work exposed to the weather and often at dangerous heights.

Lightning protection systems (LPS) are increasingly being used to enhance building resilience to natural disasters. More architects are specifying them because climate change is increasing the frequency of lightning strikes, and the growing use of electronic devices in buildings make them vulnerable to lightning surges.

Lightning protection installers are among the first trades on a job site and one of the last to leave; grounding may have to be installed simultaneously with foundations and final connections cannot be made until all building systems are in place.

The Maryville, Mo.-based Lightning Protection Institute (LPI) has certification programs for journeymen and master installers. An advanced Master Installer/Designer certificate is also available; it is crucial because project architects typically delegate design authority to the lightning protection contractor. The installer/designer must then meet stringent standards issued by the Quincy, Mass.-based National Fire Protection Association; Northbrook, Ill.-based UL LLC; and LPI.

COMPONENTS

Most of an LPS is below roof level. The most obvious above-roof components are air terminals, formerly called lightning rods. They must be located at the highest points on a roof. Depending on the building’s size and configuration, additional air terminals are required around the roof perimeter at intervals not exceeding 20 feet, within the field of the roof, on rooftop equipment and as dictated by the standards. Air terminals can be as slender as 3/8-inch diameter and as short as 10-inches tall; larger ones can be used for decorative purposes or to meet special requirements. While most air terminals now have blunt tips, pointed ones are still encountered and can be a hazard to the unwary.

Air terminals are interconnected by conductors—typically multi-strand cables that can safely carry up to 3 million volts of lightning to ground. Conductors must also be used to bond rooftop equipment and metal components to ground. In most buildings, through-roof penetrations are required so the down conductors can be run inside the structure; the penetrations can be sealed with typical flashing details. If conductors are exposed to view, they should be located in the least conspicuous locations and follow the building’s architectural lines.

Every wire entering the building must have a surge-protective device on it, and these are sometimes mounted above the roof. A variety of mounting devices, connectors, fasten- ers and adhesives are also required. All LPS components should be listed by UL specifically for lightning protection.

LPS components are typically cop- per or aluminum. To prevent galvanic action with roofing and flashings, copper components should be used with copper roofing and aluminum components with steel or aluminum roofing.

Cables interconnect the air terminals (on top of the parapet) to roof penetration (foreground) and other metal items, such as the rooftop exhaust fans and their anchorage points. Interconnections are vital to the function of the lightning protection system.

Cables interconnect the air terminals (on top of the parapet) to roof penetration (foreground) and other metal items, such as the rooftop exhaust fans and their anchorage points. Interconnections are vital to the function of the lightning protection system.

CONSTRUCTION

Before getting on the job, the roofer, LPS installer, and general contractor should agree on project schedule and roof access, as well as review proposed locations of lightning protection components. Penetrations, especially, should be located and marked prior to roofing so they can be found afterward.

The roofing manufacturer should be consulted for its recommendations. Adhesives, for example, must be compatible with the roofing, and some manufacturers require an extra layer of membrane under attachment points.

For added assurance, the building owner should have UL or LPI Inspection Service inspect the job and certify the LPS was properly installed.

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The Building Industry Is Working to Reduce Long-term Costs and Limit Disruptions of Extreme Events

“Resilience is the ability to prepare for and adapt to changing conditions and to withstand and recover rapidly from deliberate attacks, accidents, or naturally occurring threats or incidents.” —White House Presidential Policy Directive on Critical Infrastructure Security and Resilience

In August 2005, Hurricane Katrina made landfall in the Gulf Coast as a category 3 storm. Insured losses topped $41 billion, the costliest U.S. catastrophe in the history of the industry. Studies following the storm indicated that lax enforcement of building codes had significantly increased the number and severity of claims and structural losses. Researchers at Louisiana State University, Baton Rouge, found that if stronger building codes had been in place, wind damages from Hurricane Katrina would have been reduced by a staggering 80 percent. With one storm, resiliency went from a post-event adjective to a global movement calling for better preparation, response and recovery—not if but when the next major disaster strikes.

CHALLENGES OF AN AGING INFRASTRUCTURE

We can all agree that the U.S. building stock and infrastructure are old and woefully unprepared for climatic events, which will occur in the years ahead. Moving forward, engineering has to be more focused on risk management; historical weather patterns don’t matter because the past is no longer a reliable map for future building-code requirements. On community-wide and building-specific levels, conscientious groups are creating plans to deal with robust weather, climatic events and national security threats through changing codes and standards to improve their capacity to withstand, absorb and recover from stress.

Improvements to infrastructure resiliency, whether they are called risk-management strategies, extreme-weather preparedness or climate-change adaptation, can help a region bounce back quickly from the next storm at considerably less cost. Two years ago, leading groups in America’s design and construction industry issued an Industry Statement on Resiliency, which stated: “We recognize that natural and manmade hazards pose an increasing threat to the safety of the public and the vitality of our nation. Aging infrastructure and disasters result in unacceptable losses of life and property, straining our nation’s ability to respond in a timely and efficient manner. We further recognize that contemporary planning, building materials, and design, construction and operational techniques can make our communities more resilient to these threats.”

With these principles in mind, there has been a coordinated effort to revolutionize building standards to respond to higher demands.

STRENGTHENING BUILDING STANDARDS

Resiliency begins with ensuring that buildings are constructed and renovated in accordance with modern building codes and designed to evolve with change in the built and natural environment. In addition to protecting the lives of occupants, buildings that are designed for resilience can rapidly re-cover from a disruptive event, allowing continuity of operations that can liter- ally save lives.

Disasters are expensive to respond to, but much of the destruction can be prevented with cost-effective mitigation features and advanced planning. A 2005 study funded by the Washington, D.C.-based Federal Emergency Management Agency and conducted by the Washington-based National Institute of Building Sciences’ Multi-hazard Mitigation Council found that every dollar spent on mitigation would save $4 in losses. Improved building-code requirements during the past decade have been the single, unifying force in driving high-performing and more resilient building envelopes, especially in states that have taken the initiative to extend these requirements to existing buildings.

MITIGATION IS COST-EFFECTIVE IN THE LONG TERM

In California, there is an oft-repeated saying that “earthquakes don’t kill people, buildings do.” Second only to Alaska in frequency of earthquakes and with a much higher population density, California has made seismic-code upgrades a priority, even in the face of financial constraints. Last year, Los Angeles passed an ambitious bill requiring 15,000 buildings and homes to be retrofitted to meet modern codes. Without the changes, a major earth- quake could seriously damage the city’s economic viability: Large swaths of housing could be destroyed, commercial areas could become uninhabitable and the city would face an uphill battle to regain its economic footing. As L.A. City Councilman Gil Cedillo said, “Why are we waiting for an earthquake and then committed to spending billions of dollars, when we can spend millions of dollars before the earthquake, avoid the trauma, avoid the loss of afford- able housing and do so in a preemptive manner that costs us less?”

This preemptive strategy has been adopted in response to other threats, as well. In the aftermath of Hurricane Sandy, Princeton University, Princeton, N.J., emerged as a national example of electrical resilience with its microgrid, an efficient on-campus power-generation and -delivery network that draws electricity from a gas-turbine generator and solar-panel field. When the New Jersey utility grid went down in the storm, police, firefighters, paramedics and other emergency-services workers used Princeton University as a staging ground and charging station for phones and equipment. It also served as a haven for local residents whose homes lost power. Even absent a major storm, the system provides cost efficiency, reduced environmental impact and the opportunity to use renewable energy, making the initial investment a smart one.

ROOFING STANDARDS ADAPT TO MEET DEMANDS

Many of today’s sustainable roofing standards were developed in response to severe weather events. Wind-design standards across the U.S. were bolstered after Hurricane Andrew in 1992 with minimum design wind speeds rising by 30-plus mph. Coastal jurisdictions, such as Miami-Dade County, went even further with the development of wind- borne debris standards and enhanced uplift design testing. Severe heat waves and brown-outs, such as the Chicago Heat Wave of 1995, prompted that city to require cool roofs on the city’s buildings.

Hurricane Sandy fostered innovation by demonstrating that when buildings are isolated from the supply of fresh water and electricity, roofs could serve an important role in keeping building occupants safe and secure. Locating power and water sources on rooftops would have maintained emergency lighting and water supplies when storm surges threatened systems located in basement utility areas. Thermally efficient roofs could have helped keep buildings more habitable until heating and cooling plants were put back into service.

In response to these changes, there are many opportunities for industry growth and adaptation. Roof designs must continue to evolve to accommodate the increasing presence of solar panels, small wind turbines and electrical equipment moved from basements, in addition to increasing snow and water loads on top of buildings. Potential energy disruptions demand greater insulation and window performance to create a habitable interior environment in the critical early hours and days after a climate event. Roofing product manufacturers will work more closely with the contractor community to ensure that roofing installation practices maximize product performance and that products are tested appropriately for in-situ behavior.

AVERTING FUTURE DISASTERS THROUGH PROACTIVE DESIGN

Rather than trying to do the minimum possible to meet requirements, building practitioners are “thinking beyond the code” to design structures built not just to withstand but to thrive in extreme circumstances. The Tampa, Fla.-based Insurance Institute for Business & Home Safety has developed an enhanced set of engineering and building standards called FORTIFIED Home, which are designed to help strengthen new and existing homes through system-specific building upgrades to reduce damage from specific natural hazards. Research on roofing materials is ongoing to find systems rigorous enough to withstand hail, UV radiation, temperature fluctuations and wind uplift. New techniques to improve roof installation quality and performance will require more training for roofing contractors and more engagement by manufacturers on the installation of their products to optimize value.

Confronted with growing exposure to disruptive events, the building industry is working cooperatively to meet the challenge of designing solutions that provide superior performance in changing circumstances to reduce long-term costs and limit disruptions. Achieving such integration requires active collaboration among building team members to improve the design process and incorporate new materials and technologies, resulting in high-performing structures that are durable, cost- and resource-efficient, and resilient so when the next disruptive event hits, our buildings and occupants will be ready.

Denver International Airport Is Reroofed with EPDM after a Hailstorm

The millions of passengers who pass through Denver International Airport each year no doubt have the usual list of things to review as they prepare for a flight: Checked baggage or carry-on? Buy some extra reading material or hope that the Wi-Fi on the plane is working? Grab
a quick bite before takeoff or take your chances with airline snacks?

The storm created concentric cracks at the point of hail impacts and, in most cases, the cracks ran completely through the original membrane.

The storm created concentric cracks at the point of hail impacts and, in most cases, the cracks ran completely through the original membrane.

Nick Lovato, a Denver-based roofing consultant, most likely runs through a similar checklist before each flight. But there’s one other important thing he does every time he walks through DIA. As he crosses the passenger bridge that connects the Jeppeson Terminal to Gate A, he always looks out at the terminal’s roof and notices with some pride that it is holding up well. Fifteen years ago, after a hailstorm shredded the original roof on Denver’s terminal building, his firm, CyberCon, Centennial, Colo., was brought in as part of the design team to assess the damage, assist in developing the specifications and oversee the installation of a new roof that would stand up to Denver’s sometimes unforgiving climate.

HAIL ALLEY

DIA, which opened in 1995, is located 23 miles northeast of the metropolitan Denver area, on the high mountain desert prairie of Colorado. Its location showcases its spectacular design incorporating peaked tent-like elements on its roof, meant to evoke the nearby Rocky Mountains or Native American dwellings or both. Unfortunately, this location also places the airport smack in the middle of what is known as “Hail Alley”, the area east of the Rockies centered in Colorado, Nebraska and Wyoming. According to the Silver Spring, Md.- based National Weather Service, this area experiences an average of nine “hail days” a year. The reason this area gets so much hail is that the freezing point—the area of the atmosphere at 32 F or less—in the high plains is much closer to the ground. In other words, the hail doesn’t have time to thaw and melt before it hits the ground.

Not only are hail storms in this area relatively frequent, they also produce the largest hail in North America. The Rocky Mountain Insurance Information Association, Greenwood Village, Colo., says the area experiences three to four hailstorms a year categorized as “catastrophic”, causing at least $25 million in damage. Crops, commercial buildings, housing, automobiles and even livestock are at risk.

Statistically, more hail falls in June in Colorado than during any other month, and the storm that damaged DIA’s roof followed this pattern. In June 2001, the hailstorm swept over the airport. The storm was classified as “moderate” but still caused extensive damage to the flat roofs over Jeppesen Terminal and the passenger bridge. (It’s important to note that the storm did not damage the renowned tent roofs.) The airport’s original roof, non-reinforced PVC single-ply membrane, was “shredded” by the storm and needed extensive repair. Lovato and his team at CyberCon assessed the damage and recommended changes in the roofing materials that would stand up to Colorado’s climate. Lovato also oversaw the short-term emergency re- pairs to the roof and the installation of the new roof.

The initial examination of the roof also revealed that the existing polystyrene rigid insulation, ranging in thickness from 4 to 14 inches, was salvageable, representing significant savings.

The initial examination of the roof also revealed that the existing polystyrene rigid insulation, ranging in thickness from 4 to 14 inches, was salvageable, representing significant savings.

Under any circumstances, this would have been a challenging task. The fact that the work was being done at one of the busiest airports in the world made the challenge even more complex. The airport was the site of round-the-clock operations with ongoing public activity, meaning that noise and odor issues needed to be addressed. Hundreds of airplanes would be landing and taking off while the work was ongoing. And three months after the storm damaged the roof in Denver, terrorists attacked the World Trade Center, making security concerns paramount.

INSPECTION AND REROOFING

Lovato’s inspection of the hail damage revealed the extent of the problems with the airport roof. The original PVC membrane, installed in 1991, was showing signs of degradation and premature plasticizer loss prior to being pummeled by the June 2001 storm. The storm itself created concentric cracks at the point of hail impacts and, in most cases, the cracks ran completely through the membrane. In some instances, new cracks developed in the membranes that were not initially visible following the storm. The visible cracks were repaired immediately with EPDM primer and EPDM flashing tape until more extensive repairs could begin. Lovato notes that while nature caused the damage to DIA, nature was on the roofing team’s side when the repairs were being made: The reroofing project was performed during a drought, the driest in 50 years, minimizing worries about leaks into the terminal below and giving the construction teams almost endless sunny days to finish their job.

The initial examination of the roof also revealed that the existing polystyrene rigid insulation, ranging in thickness from 4 to 14 inches, was salvageable, representing significant savings. Although a single-ply, ballasted roof was considered and would have been an excellent choice in other locations, it was ruled out at the airport given that the original structure was not designed for the additional weight and substantial remediation at the roof edge perimeter possibly would have been required.

Lovato chose 90-mil black EPDM membrane for the new roof. “It’s the perfect roof for that facility. We wanted a roof that’s going to perform. EPDM survives the best out here, given our hailstorms,” he says. A single layer of 5/8-inch glass-faced gypsum board with a primed surface was installed over the existing polystyrene rigid insulation (secured with mechanical fasteners and metal plates) to provide a dense, hail-resistant substrate for the new membrane.

In some areas adjacent to the airport’s clerestory windows, the membrane received much more solar radiation than other areas of the roof.

In some areas adjacent to the airport’s clerestory windows, the membrane received much more solar radiation than other areas of the roof.

In some areas adjacent to the airport’s clerestory windows, the membrane received much more solar radiation than other areas of the roof. When ambient temperatures exceeded 100 F, some melting of the polystyrene rigid insulation occurred. “That section of the roof was getting double reflection,” Lovato points out. To reduce the impact of this reflection, the roof was covered with a high-albedo white coating, which prevented any further damage to the top layer of the polystyrene rigid insulation board and also met the aesthetic requirements of the building.

LONG-TERM SOLUTION

Lovato’s observations about the durability of EPDM are backed up by field experience and controlled scientific testing. In 2005, the EPDM Roofing Association, Washington, D.C., commissioned a study of the impact of hail on various roofing membranes. The study, conducted by Jim D. Koontz & Associates Inc., Hobbs, N.M., showed EPDM outperforms all other available membranes in terms of hail resistance. As would be expected, 90-mil membrane offers the highest resistance against punctures. But even thinner 45-mil membranes were affected only when impacted by a 3-inch diameter ice ball at 133.2 feet per second, more than 90 mph—extreme conditions that would rarely be experienced even in the harshest climates.

Lovato travels frequently, meaning he can informally inspect the DIA roof at regular intervals as he walks through the airport. He’s confident the EPDM roof is holding up well against the Denver weather extremes, and he’s optimistic about the future. With justified pride, Lovato says, “I would expect that roof to last 30-plus years.”

PHOTOS: CyberCon

Roof Materials

90-mil Non-reinforced EPDM: Firestone Building Products
Gypsum Board: 5/8-inch DensDeck Prime from Georgia-Pacific
Plates and Concrete Fasteners: Firestone Building Products
White Elastomeric Coating: AcryliTop from Firestone Building Products
Existing Polystyrene: Dow

Better Understand Why the Combination of Moisture and Concrete Roof Decks Is Troublesome

The primary function of a well-built and well-designed roofing system is to prevent water from moving through into the building below it. Yet, as the Rosemont, Ill.-based National Roofing Contractors Association has observed, an increasing number of “good roofs” installed on concrete roof decks have failed in recent years. Blistering, de-bonding and substrate buckling have occurred with no reports of water leakage. Upon investigation, the roofing materials and substrates are found to be wet and deteriorated.

Wagner Meters offers moisture-detection meters for concrete. The meters are designed to save time and money on a project or job site.

Wagner Meters offers moisture-detection meters for concrete. The meters are designed to save time and money on a project or job site.

Why is this? One potential cause is trapped moisture; there are numerous potential sources of trapped moisture in a structure. Let’s examine the moisture source embedded within the concrete roof deck.

WHY DOES THIS MOISTURE BECOME TRAPPED?

It often starts with the schedule. In construction, time is money, and faster completion means lower cost to the general contractor and owner. Many construction schedules include the installation of the roof on the critical path because the interior building components and finishes cannot be completed until the roof has been installed. Therefore, to keep the project on schedule, roofers are pressured to install the roof soon after the roof deck has been poured. Adding to the pressure are contracts written so the general contractor receives a mile- stone payment once the roof has been installed and the building has been topped out.

Historically, roofers wait a minimum of 28 days after the roof deck is poured before starting to install a new roof. This is the concrete industry’s standard time for curing the concrete before testing and evaluating the concrete’s compressive strength. Twenty-eight days has no relation to the dryness of a concrete slab. Regardless, after 28 days the roofer may come under pres- sure from the general contractor to install the roof membrane. The concrete slab’s surface may pass the historic “hot asphalt” or the ASTM D4263 Standard “plastic sheet” test, but the apparently dry surface can be deceptive. Curing is not the same as drying, and significant amounts of water remain within a 28-day-old concrete deck. Depending on the ambient conditions, slab thickness and mixture proportions, the interior of the slab will likely have a relative humidity (RH) well over 90 percent at 28 days.

FROM WHERE DOES THE WATER COME?

Upon placing the concrete slab, the batch water goes to several uses. Portland cement reacts with water through the hydration process, creating the glue that holds concrete together. The remaining water held in capillary pores can be lost through evaporation, but evaporation is a slow, diffusion-based process. The diffusion rate of concrete is governed by the size and volume of capillary pores which, in turn, are controlled by the water/cement (w/cm) ratio. The total volume of water that will be lost is controlled by the degree of hydration, which is primarily related to curing and w/cm.

A 4-inch-thick concrete slab releases about 1 quart of water for each square foot of surface area. If a roof membrane is installed before this water escapes the slab, it can become trapped and collect beneath the roof system. The water does not damage the concrete, but it can migrate into the roofing system—and that’s when problems begin to occur. For instance, moisture that moves into the roofing system can:

  • Reduce thermal performance of the insulation.
  • Cause the insulation, cover board, adhesive or fasteners to lose strength, making the roofing system susceptible to uplift or damage from wind, hail or even foot traffic.
  • Lead to dimensional changes in the substrate, causing buckling and eventually damaging the roof membrane.
  • Allow mold growth.

A number of factors compound the problem. In buildings where a metal deck is installed, moisture cannot exit the slab through its bottom surface. Instead, the moisture is forced to exit the slab by moving upward. Eliminating one drying surface almost doubles the length of drying time of a concrete slab. The small slots cut in ventilated metal decking have little effect on reducing this drying time.

Ambient conditions also affect the drying rate of a concrete slab since it readily absorbs and retains moisture. Additional moisture may enter an unprotected roof slab from snow cover, rain or dew. Even overcast days will slow the rate of drying.

A MODERN-DAY PROBLEM

Before the introduction of today’s low-VOC roofing materials, historic roof systems didn’t experience as many of these moisture issues. Typically, they were in- stalled onto concrete decks on a continuous layer of hot asphalt adhesive that bonded the insulation to the deck. This low-permeable adhesive acted as a vapor retarder and limited the rate of moisture migrating from the concrete into the roofing assembly. As a result, historic roof systems were somewhat isolated from moisture coming from the concrete slab.

Many of today’s single-ply roof membranes are not installed with a vapor retarder. Moisture is able to migrate from the concrete slab into the roof materials. Modern insulation boards are often faced with moisture-sensitive paper facers and adhered to substrates with moisture-sensitive adhesives. These moisture-sensitive paper facers and adhesives are causing many of the problems.

Rene Dupuis of Middleton, Wis.- based Structural Research Inc. recently presented a paper to the Chicago Roofing Contractors Association on the subject. Some of his findings include the following:

  • Due to air-quality requirements, government regulations curtailed the use of solvent-based adhesives because they are high in VOCs. Consequently, manufacturers changed to water-based adhesives because they are lower in VOCs, have low odor, are easy to apply and pro- vide more coverage.
  • There can be several drawbacks to water-based bonding adhesives. One is that they may be moisture sensitive. Moisture and alkaline salts migrating into roof systems from concrete decks can trigger a negative reaction with some water-based adhesives. This reaction can cause the adhesives to revert to a liquid, or it may alter or delay the curing of some foam-based adhesives. Some adhesive manufacturers have recognized these problems and have be- gun reformulating their adhesives to address these drawbacks.
  • Negative reactions also occur when moisture-sensitive paper facers come into contact with moisture. This reaction typically results in decay, mold growth and loss of cohesive strength. Moisture in the roof system may also cause gypsum and wood-fiber-based cover boards to lose cohesive strength.

Dupuis noted moisture from any source can compromise adhered roof systems with wind uplift when attached to paper insulation or gypsum board. He also said facer research clearly shows paper facers suffer loss of strength as moisture content increases.

PHOTOS: Wagner Meters

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Attic Ventilation in Accessory Structures

Construction Code Requirements for Proper Attic Ventilation Should Not Be Overlooked in Buildings That Don’t Contain Conditioned Space

The 2015 International Residential Code and International Building Code, published by the International Code Council, include requirements for attic ventilation to help manage temperature and moisture that could accumulate in attic spaces. Although the code requirements are understood to apply to habitable buildings, not everyone understands how the code addresses accessory structures, like workshops, storage buildings, detached garages and other buildings. What’s the answer? The code treats all attic spaces the same, whether the space below the attic is conditioned or not. (A conditioned space is a space that is heated and/or cooled.)

The 2015 International Residential Code and International Building Code include requirements for attic ventilation to help manage temperature and moisture that could accumulate in attic spaces. Although the code requirements are understood to apply to habitable buildings, not everyone understands the code also addresses accessory structures, like workshops, storage buildings, detached garages and other buildings.

The 2015 International Residential Code and International Building Code include requirements for attic ventilation to help manage temperature and moisture that could accumulate in attic spaces. Although the code requirements are understood to apply to habitable buildings, not everyone understands the code also addresses accessory structures, like workshops, storage buildings, detached garages and other buildings.


The administrative provisions of the IRC that set the scope for the code are found in Chapter 1. Section R101.2 and read:

    The provisions of the International Residential Code for One- and Two-family Dwellings shall apply to the construction, alteration, movement, enlargement, replacement, repair, equipment, use and occupancy, location, removal and demolition of detached one- and two-family dwellings and townhouses not more than three stories above grade plane in height with a separate means of egress and their accessory structures not more than three stories above grade plane in height.

Let’s clear up any confusion about the code. The ventilated attic requirements in the 2015 IRC include the following language in Section R806.1:

    Enclosed attics and enclosed rafter spaces formed where ceilings are applied directly to the underside of roof rafters shall have cross ventilation for each separate space by ventilating openings protected against the entrance of rain or snow.

An accessory structure is actually defined in the IRC:

    ACCESSORY STRUCTURE. A structure that is accessory to and incidental to that of the dwelling(s) and that is located on the same lot.

The IBC also includes attic ventilation requirements that are essentially the same as the IRC. Section 101.2 of the 2015 IBC contains this text:

    The provisions of this code shall apply to the construction, alteration, relocation, enlargement, replacement, repair, equipment, use and occupancy, location, maintenance, removal and demolition of every building or structure or any appurtenances connected or attached to such buildings or structures.

This requirement for ventilated at-tics in accessory structures in the IBC and IRC is mandatory unless the attic is part of the conditioned space and is sealed within the building envelope. Unvented, or sealed, attics allow any ducts located in the attic to be inside the conditioned space, which can have beneficial effects on energy efficiency. For accessory structures, which are typically unheated, that provision does not apply.

It’s important to note the codes do contain detailed requirements for the design and construction of sealed at-tics to reduce the chance of moisture accumulation in the attic. These requirements have been in the codes for a relatively short time and remain the subject of continued debate at ICC as advocates of sealed attics work to improve the code language in response to concerns about performance issues from the field.

Traditional construction methods for wood-framed buildings include ventilated attics (with insulation at the ceiling level) as a means of isolating the roof assembly from the heated and cooled space inside the building. Attic ventilation makes sense for a variety of reasons. Allowing outside air into the attic helps equalize the temperature of the attic with outdoor space. This equalization has several benefits, including lower roof deck and roof covering temperatures, which can extend the life of the deck and roof covering. However, it is not just temperature that can be equalized by a properly ventilated attic. Relative humidity differences can also be addressed by vented attics. Moisture from activity in dwelling units including single-family residences and other commercial occupancies can lead to humidity entering the attic space by diffusion or airflow. It is important to ensure moisture is removed or it can remain in the attic and lead to premature deterioration and decay of the structure and corrosion of metal components, including fasteners and connectors.

In northern climate zones, a ventilated attic can isolate heat flow escaping from the conditioned space and reduce the chance of uneven snow melt, ice dams, and icicle formation on the roof and eaves. Ice damming can lead to all kinds of moisture problems for roof assemblies; it is bad enough that roof assemblies have to deal with moisture coming from inside the attic, but ice damming can allow water to find its way into roof covering assemblies by interrupting the normal water-shedding process. For buildings with conditioned space, the attic can isolate the roof assembly from the heat source but only if there is sufficient ceiling insulation, properly installed over the top of the wall assemblies to form a continuous envelope. Failure to ensure continuity in the thermal envelope is a recipe for disaster in parts of the country where snow can accumulate on the roof.

Accessory buildings, like workshops, that occasionally may be heated with space heaters or other sources are less likely to have insulation to block heat flow to the roof, which can result in ice damming. Ventilating the attic can prevent this phenomenon.

Accessory buildings, like workshops, that occasionally may be heated with space heaters or other sources are less likely to have insulation to block heat flow to the roof, which can result in ice damming. Ventilating the attic can prevent this phenomenon.


For unheated buildings in the north, ice damming is less likely to occur, unless the structure is occasionally heated. Accessory buildings, like workshops, that might be heated from time to time with space heaters or other sources are less likely to have insulation to block heat flow to the roof. In these situations, a little heat can go a long way toward melting snow on the roof.

While the ice damming and related performance problems are a real concern even for accessory structures, it is the removal of humidity via convective airflow in the attic space that is the benefit of ventilated attics in accessory structures. We know that moisture will find its way into buildings. Providing a way for it to escape is a necessity, especially for enclosed areas like attics.

There are many types of accessory structures, and some will include conditioned space. Depending on the use of the structure, moisture accumulation within the building will vary. For residential dwelling units, building scientists understand the normal moisture drive arising from occupancy. Cooking, laundering and showering all contribute moisture to the interior environment.

The IRC and IBC include requirements for the net-free vent area of intake (lower) and exhaust (upper) vents and also require the vents be installed in accordance with the vent manufacturer’s installation instructions. The amount of required vent area is reduced when a balanced system is installed; most ventilation product manufacturers recommend a balance between intake and exhaust. The IRC recommends that balanced systems include intake vents with between 50 to 60 percent of the total vent area to reduce the chance of negative pressure in the attic system, which can draw conditioned air and moisture from conditioned space within the building. This is less of an issue for non-habitable spaces from an energy-efficiency perspective, but moisture accumulation is a concern in all structures.

PHOTOS: Lomanco Vents

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A Roofing Contractor Drives Sales and Leads with Fast and Easy Energy-efficiency Financing

After 15 years in the roofing business, I’ve seen countless construction, design trends and sales methods change over time. The one thing that has always stayed the same? That first discussion with the customer around the kitchen table, looking at the scope of the job and then getting right down to finances. It’s the conversation that can make or break a project: Can the customer get the financing he or she needs to complete the job? Do we need to offer other options? Scale back? Or, even better, can we expand the job and sell into higher-quality products and designs built to last?

Supported by local governments, the YgreneWorks PACE program allows property owners to perform energy-efficiency and resiliency upgrades on their homes or businesses with zero down, a low interest rate and simple annual payments made through their property taxes.

Supported by local governments, the YgreneWorks PACE program allows property owners to perform energy-efficiency and resiliency upgrades on their homes or businesses with zero down, a low interest rate and simple annual payments made through their property taxes.

Regardless of project size or complexity, customers have two top-of-mind factors when considering a reroof: cost and time. As roofing contractors, we strive to deliver the highest-value renovation in the shortest time possible. To keep our team at Cal-Vintage Roofing of Northern California, Sacramento, at the industry forefront with competitive product and service offerings, we’ve developed a partnership with Santa Rosa, Calif.-based Ygrene Energy Fund to offer customers the latest in financing. The result has been a much happier kitchen-table conversation, alleviating customer concerns about reroofing costs and ultimately increasing our business by 20 percent.

KEEPING PACE WITH A GROWING TREND

Ygrene Energy Fund is a leading multi-state provider of Property Assessed Clean Energy (PACE) financing. Supported by local governments, the YgreneWorks PACE program allows property owners to perform energy-efficiency and resiliency upgrades on their homes or businesses with zero down, a low interest rate and simple annual payments made through their property taxes. These “green” roofing projects can include everything from cool roof shingles that slow heat build and save on electricity costs to reflective insulation providing a better thermal barrier for a building.

Increasingly, Cal-Vintage customers are more concerned with how projects impact the environment and are always interested in ways to lower utility bills. In fact, many PACE-qualifying upgrades are now being mandated by law; for instance, Title 24, Part 6, of the California Code of Regulations requires that residential and nonresidential buildings adhere to strict energy-reduction standards mandated by local governments. This has resulted in an uptick in owners who need major roof renovations and also need a way to afford the upgrade. As similar laws gain popularity amongst U.S. cities and states, PACE is a valuable tool for customers looking for better reroof financing options. As a large roofing company, we at Cal-Vintage must take it upon ourselves to offer every way to comply with these rules.

To qualify, Ygrene considers the equity in the property, not the personal credit of the property owner, unlocking finance doors for entire groups of customers. So far, more than 40 Cal-Vintage clients have taken advantage of the PACE option to avoid dipping into savings, escape lengthy paperwork and skip extensive background checks. Securing traditional reroofing loans can be a long and difficult process. With PACE financing, our customers have been able to complete larger, longer-lasting projects faster because the financing comes through in two to three days rather than two to three weeks.

BECOMING A CERTIFIED PACE CONTRACTOR

many PACE-qualifying upgrades are now being mandated by law; for instance, Title 24, Part 6, of the California Code of Regulations requires that residential and nonresidential buildings adhere to strict energy-reduction standards mandated by local governments.

Many PACE-qualifying upgrades are now being mandated by law; for instance, Title 24, Part 6, of the California Code of Regulations requires that residential and nonresidential buildings adhere to strict energy-reduction standards mandated by local governments.


Our job as roofing contractors is to provide the best value to our customers and community, and in a world of changing regulations and housing needs, this value extends to financing. The entire Cal-Vintage team is trained through Ygrene’s Certified Contractor Education program to know when and how to offer PACE financing as an option at the kitchen-table discussion.
The Ygrene education and certification program includes in-person training for our sales teams matched with webinars and online tutorials that can be accessed from the web anywhere, anytime. Topics cover all the information we need, including details about the PACE program, important consumer protections, step-by-step instructions for helping customers fill out the online application and how to ensure we receive our payment in a timely manner.

The Cal-Vintage sales team also received an in-person, individual training by a Ygrene regional area manager dedicated to our team. The training included information about program features and benefits, access to the web portal, the proposal tool and in- depth answers to our questions. As PACE requires a number of legal disclosures and approvals, our contractor team was briefed on the application and approval and funding processes so we could properly answer any custom- er questions. Additionally, Ygrene offers a support call-center to field any additional questions on the financing.

GETTING STARTED

We heard about Ygrene through a customer and reached out to the company’s local representative to become certified. The process was simple, and all of our questions were answered in the training session. Since the company’s inception, Ygrene has trained nearly 3,000 contractor companies in communities across its service territory. With $1 billion in approved applications and $350 million in closed contracts, Ygrene has been generating successful outcomes for customers and contractor partners across the U.S. Those interested in becoming a certified contractor can visit Ygrene Works’ website.

PHOTOS: CAL-VINTAGE ROOFING OF NORTHERN CALIFORNIA